Covering for airplanes and method for applying same



June 18, 1968 s, AXELROD 3,388,651

COVERING FOR AIRPLANES AND METHOD FOR APPLYING SAME Filed Jan. 28, 1966AT TO R NEYS 3,388,651 CUVERENG EUR AIRPLANES AND METHGD FR APPLYlNGSAME Sidney Axelrod, Chicago, lll., assigner to Top Flite Models, lac.,Chicago, lll. Filed San. 28, 1966, Ser. No. 523,599 Claims. (tCl.lion-'76) ABSTRACT F THE DiSCLGSURE A covering Vfor airplane frameswherein a layer of plastic film has a layer of adhesive bonded theretofor applying the plastic material to the frame. In addition, theadhesive may be colored to impart said color to the airplane while thecoloring itself is protected by the plastic. There is also disclosed amethod for applying the lilm with the adhesive bonded thereto byadhering and shrinking the same to the frame through the application ofheat and resultant cooling.

This invention relates to a covering for airplanes and more particularlyrelates to a covering for model airplanes and the method for applyingthe same. l

Model airplanes which are built for the sport of flying, normallycomprise an airplane frame covered by a light weight material.Heretofore, to properly cover these model airplanes required a greatdeal of skill andthe expenditure of many hours of effort. For example,in a commonly used prior method a thin light material of paper or silkwas placed over the frame, then wetted to cause shrinkage, after whichmany layers of dope or lacquer were placed over the material. Moreover,before one of these layers were placed on another, it was dried andafterward sanded to the proper smoothness. After this was completed, itwas still necessary to provide a finish over the airplane. Even the mostskilled found that the aforementioned method had many objectionablefeatures. The main objection, however, was the time involved in properlycovering and finishing the airplane frame. lIn fact, many who wereinterested in the flying or competitive aspect of a model airplane hobbywere discouraged from pursuing the same due to the time factor infabricating the airplane models.

Another objection `of the aforementioned method was that the thin lightmaterial initially applied over the frame was easily torn or otherwisedamaged. Furthermore, the wetting of the material frequently causeduncontrollable shrinkage which often developed into wrinkles that werenot usually able to be completely smoothed out. Hence, the material didnot have suflicient tautriess in all directions. Moreover, when applyingthe layers of dope or lacquer weight imbalances invariably resulted dueto the uneven amounts of dope or lacquer which were used in filling inthe valleys of the wrinkles in the material. This appreciably affectedthe airplanes flying performance.

It is therefore a primary object of this invention to provide a modelairplane covering that is capable of being applied over an airplaneframe at a substantial reduction of the time which was heretoforenecessary.

It is another object to provide a model airplane covering that iscapable of providing sufhcient tautness in all directions.

lt is a further object to provide an airplane covering that is notsusceptible to the occurrences of weight imbalances when applied overthe frame.

A `defect in prior model airplane coverings was the susceptibility ofthe same to lose its bond with the frame when fuel would seep into thearea between the outer surface of the covering and the frame. For somecoverings, 'access to States Patent 0 the inside was through the lapover joint which is the area where an edge of a portion of the coveringlies ori a surface of another portion of :the covering. For othercoverings which had successive layers of dope, the fuel would eat itsway through the paint finish and the dope. Still a further defect ofsome of the prior model airplane coverings was the tendency of the sameto develop a large tear from even the slightest puncture.

It is therefore another primary object to provide a covering for modelairplanes that affords a sufficiently bonded lap over joint to preventthe seepage of fuel between the plastic layer and the frame.

It is still another primary feature to provide a covering which issecurely bonded to the frame of the model airplane whereby any damage tothe covering is kept localized and does not spread to other areas.

Heretofore, the applying of a finish to the airplane for the final stepbefore the completion of the covering process, was also a timeconsu-ming task. Furthermore, when a plastic was suggested for use as apossible model airplane covering, a coloring problem immediately arosedue to the difhculty in applying paints to such coverings.

It is therefore another primary object of this invention to provide acovering for model airplanes which includes a plastic layer of materialand does not require painting or a color finishing step in order toimpart coloring to the covering.

It is a primary feature of this invention to provide a model airplanecovering which comprises a plastic outer layer and a pressure sensitiveinner adhesive layer for adhesively associating the plastic to theairplane frame.

It is another primary feature of the invention to shrink and bond aplastic material to the contours of the frame of the model airplane.

It is a further feature to insert colored material between the outerexposed layer of the covering of the airplane and the airplane frame.

It is still a further feature to provide an airplane covering that isalso adaptable as a joint or hinge for the various movable parts of themodel airplane.

For the purpose of facilitating an understanding of my invention, I haveillustrated in the accompanying drawing a preferred embodiment thereof,from an inspection of which, when considered in connection with thefollowing description, my invention, its mode of construction, assemblyand operation, and many of its advantages should be readily understoodand appreciated.

Referring to the drawing in which like characters of reference indicatecorresponding or similar parts throughout the several figures of thedrawing:

FIGURE l is a perspective view of a model airplane ernbodying theprinciples of the invention;

FIGURE 2 is a wing of a model airplane with portions of the covering cutaway to show the wing structure of the frame;

FIGURE 3 is a sectional view showing a layer of pressure sensitiveadhesive material attached between a layer of plastic material and alayer of release paper;

FIGURE 4 is a fragmentary sectional view showing the adhesive layerattached to the plastic layer and spaced from a section of the frame ofthe model airplane;

FIGURE 5 is an enlarged fragmentary sectional view showing the adhesivelayer attached to a porous frame and with portions of the adhesive layerextending into the pores of the frame;

FIGURE 6 is an enlarged fragmentary View of the tail of the modelairplane in FIGURE l, and showing in phantom movable parts thereof in anangularly displaced position;

FIGURE 7 is a sectional view taken substantially on the plane of theline '7 7 in FIGURE 6, viewed in the 3 direction indicated, and showingthe model airplane covering acting as a joint to permit movement of onesection from another; and

FIGURE 8 is a fragmentary enlarged sectional view illustrating the lapjoint on a model airplane covering where an edge of a portion of theplastic layer lies on a surface of another portion of the plastic layer.

Referring now to the drawing, the reference character 10 indicatesgenerally a model airplane embodying the principles of the invention.The model airplane 10 may be made to any suitable outer configurationand FIGURE l illustrates a model of a conventional airplane having apair of wings 12 and a tail 14 iixedly attached to the main body sectionor fuselage 16 when operatively assembled together. A covering 18extends over substantially the entire airplane frame and is generallyattached to the main parts thereof prior to the assembling of the same.

The covering 18 comprises an outer layer or lilm of a clear plasticmaterial 24 and an inner layer of adhesive 26 which is adhesivelyattached to the inside surface of the plastic layer 24 (FIGS. 4 and 5).The adhesive layer 26 may be of the pressure sensitive type. Hence, whenstoring the adhesive plastic prior to use as a covering 18, the adhesive26 is preferably releasably attached to a sheet of release paper 30(FIG. 3). A polyester resin such as Mylar has been found to be anacceptable plastic material. An acrylic material has been successfullyused as a pressure sensitive adhesive.

Coloring for the covering 18 is provided in the adhesive layer 26. Dyes,such as inorganic pigments of the type used in paints, may beincorporated into the adhesive to provide the various colors. In thismanner, the coloring of the model airplane is protected by the plasticouter layer 44 and, hence, does not wear away due to the exposure to theelements nor dissolve from the effects of fuel.

Alternatively, a dry adhesive layer 26 which is activated by heat or asolvent is also within the contemplation of this invention. This wouldinclude an initially sticky adhesive which may dry out due to exposure.By an application of a suitable material to the exposed face of apressure sensitive adhesive, the same may also be converted `into a dryadhesive. To provide such a conversion, a powder made from a zincstearate material was sprinkled over the exposed face of a pressuresensitive adhesive causing the same to loose its tackiness. Aftercovering a portion of the model airplane frame and applying heat andpressure to the plastic layer 26, the adhesive was activated and causeda bond between the plastic and the frame. Zinc stearate is referred tomerely for example, and other materials that would cause the cnvertingof the pressure sensitive adhesive to a dry adhesive and the activationof the adhesive with heat, would also be suitable.

With the adhesive being initially dry rather than tacky, the adhesivecoated plastic may be conveniently stored in rolls rather than sheetsand any particular length thereof could be easily dispensed therefromand shipped to the purchaser. Also, with a dry adhesive the adhesivecoated plastic is manipulable into the proper position with greaterfacility, and furthermore there would be substantially less possibilityof the plastic wrinkling when applying the same to the airplane frame.

The method or process for applying the covering to the frame will now hedescribed in conjunction with the drawing. In applying the covering 18to the frame of the model airplane, the length and shape constitutingthe covering or portions thereof, are initially cut out from a sheetcomprising a layer of clear plastic material 24 and a layer of coloredadhesive 26 coated to the plastic and releasably attached to a layer ofrelease paper 30 (FIG. 3). Of course, if the adhesive were a dryadhesive, the layer of release paper would not be necessary. When therelease paper 30 is removed from the cut out adhesive coated plastic,the same as shown in FIG. 4, may now be applied to a section 31 of themodel airplane frame.

After applying,r the adhesive layer 26 to the frame, the plastic layer24 is smoothened out in every direction to remove wrinkles therefrom andto press the adhesive layer 26 in tight contact with the area of theairplane it covers. Although the smoothing out of the plastic layer 24straightens the same, it will be immediately apparent that the tautnessis substantially less than desired.

To provide suicient tautness and to effect a secure bond between theframe of the model airplane 10 and the plastic layer 24, it is necessaryto apply heat to the plastic layer 24 in order to cause the same tobecome more pliable. When the plastic layer cools it shrinks to thecontours of the frame. Heat may be applied with an electric iron or ablower or other suitable heating devices. Preferably, heat shouldinitially be applied to the outer perimeters of the frame to cause theplastic layer 24 thereat lto make a secure bond with the frame. Then,heat is applied to the area of the plastic layer 24 between the bondedperimeters and upon cooling the plastic shrinks tight against the frame.With particular reference to FIGURE 2, the initial application of heat.is applied along the lateral edges 32 of the wing 12 to bond theplastic thereto. When heat is applied to the surface of the plasticlayer 24 between the edges 32, the same upon cooling shrinks over theribs 34. The heating of the plastic also causes the adhesive to bond theplastic to the ribs 34. Moreover, the shrinking of the plastic causes apressure against the frame that insures a secure bond.

However, the method of the invention does not require that the coveringbe initially placed on the frame in a careful and smooth manner or thatthe covering be wrinkle free. The heating of the plastic layer willremove all traces of wrinkles and provide a skin tight and wrinkle freecovering.

For extremely porous frames, such as those made from balsa wood, theheat :is applied to the lateral edges for a suicient length of time topermit a portion of the adhesive layer 26 to impregnate the pores andthereby securely bond the plastic layer 24 to the frame edges, as isparticularly shown in FIGURE 5. To insure that portions of the adhesivelayer 26 irnpregnate into the top surface of the porous frame, it may benecessary to apply sufficient pressure with the heat in order tocompress the adhesive and force the same into the pores. With theadhesive impregnated in the pores, a secure bond is made with theirregularly shaped walls of the pores.

Turning to FIGURE 8, the heating of the edge of the adhesive layer 26acauses the plastic layer 24a to make a secure bond with plastic layer2412 at the lap joint or seam 36. The lap joint 36 on the covering 1S isthe area where an edge of a portion of the plastic layer lies on thesurface of another portion of the plastic layer. The part of thecovering 18 at the joint 36 is compressed tight together with heat andpressure to afford a secure bond thereat. This prevents the seepage ofthe fuel used by the model airplane in between the plastic layer 24 andthe frame. Moreover, the heat appears to seal or cure the adhesive andprevent the same from dissolving from the fuel. During the flyingoperation of the model airplane, a fuel :film often forms on thecovering and heretofore would cause the dissolving or loosening of thecovering from the trame.

With reference to FIGURES 6 and 7, the tail 14 includes a rudder 38, aiin 4t) and stabilizer 42. Stabilizer 42 includes a movable elevator 44.The movement of rudder 38 and elevator 44 may be controlled. As shown inFIGURE 7, the covering 13 is adaptable to provide a movable joint 50 topermit the rudder 3S to be pivoted outwardly away from iin 40. Toaccomplish this without additional parts, the covering 13 on the uppersurface of the rudder 38 and iin 40 does not extend across the adjacentedges thereof. However, the covering 18 on the lower surfaces extendsacross the adjacent edges to afford a pivot 50 whereby rudder 38 may bepivoted away from lin 40 as shown in phantom in FIGURE 7. Note, that theadjacent edges of the iin and rudder are angled to permit the movementof the rudder upward or downward (FIG. 7). Similarly the aileron |56 onthe wing 12 may use the covering 18 for a pivot joint.

From the foregoing description and drawing, it should be apparent that Ihave provided a novel covering for model airplanes and the method forapplying the same. Although the covering was described in conjunctionwith model airplanes, the principles of the invention may also beapplicable for the regular size airplane as well. The plastic adhesivecoated material after being applied over the airplane frame is heatedand upon cooling shrinks to the contour of the frame. The heat alsocauses the adhesive to bond the plastic to the frame. Hence, if apuncture occurs in the airplane covering the damage is therebylocalized. Moreover, by heating the seam or lap over joint 36 of thecovering 18, a secure bond is made with another portion of the covering18, as illustrated in FIGURE 8. This prevents the seepage of fuelbetween the plastic layer and the frame. Furthermore, the coveringherein is further adaptable to provide a pivoted joint for manipulatingthe airplane rudder or aileron and does not require attachment ofadditional parts that were previously required.

The adhesive layer 26 is dyed to a particular color and hence theapplication of the covering to the frame has eliminated the need topaint the airplane. Therefore, by predetermining the airplane colorscheme, the various strips of adhesive plastic applied to the framewould correspond accordingly to the desired coloring. Moreover, any dirtand grime that collects on the plastic layer may be wiped cleantherefrom and the airplane, even after much use, would have a new glossyappearance. Also, by having the coloring inside the adhesive and theplastic layer thereover, there is no damage or chipping of paint which,heretofore, invariably occurred after even the slightest use.

It is believed that my invention, its mode of construction and assembly,and many of its advantages should be readily understood from theforego-ing without further description and it should also be manifestthat while a preferred embodiment of the invention has been shown anddescribed for illustrative purposes, the structural details arenevertheless capable of wide variation within the purview of myinvention as defined in the appended claims.

What I claim and desire to secure by Letters Patent of the United Statesis:

1. In combination with an airplane frame, a covering material appliedthereto, said covering material comprising a flexible, clear heat-shrunkfilm of polyester resin precoated over substantially the entire surfaceof one side with a layer of adhesive containing coloring materialinterspersed therewith, said layer of adhesive and interspersed coloringmaterial being bonded to said iilm.

2. The covering for airplane frames of claim 1, wherein said hlm istransparent whereby the color of said coloring material is visiblethrough the lm but the material is insulated and protected fromextraneous elements and materials by said film.

3. ln a method for covering an airplane frame with a covering materialcomprising a flexible, clear, heatshrinkahle film of polyester resinpre-coated on one side with a layer of adhesive containing coloringmaterial, the steps of applying a predetermined length of said coveringmaterial to a section of said frame so that the film comprises the outerside thereof and thereafter applying heat to the film to cause the lm toshrink tautly to the contours of the frame and the adhesive to bond thelm to the frame.

d. The method of claim 3 wherein heat is applied to a lirst part of saidlm at the perimeters of said frame to cause a first portion of theadhesive layer at the perimeters to bond said first part of the filmwith the frame, heat is applied to a second part of said lm between thebonded pcrimeters to cause the same to become more pliable and to causea second portion of the adhesive layer to bond said second part of thefilm to the frame, and cooling said second part of the film to cause thesame to shrink tautly tothe contours ofthe frame.

5. A covering for a model airplane frame comprising: an outer plasticlm; an adhesive layer of material between said plastic film and saidframe, said adhesive layer securing said plastic film to the frame; andsaid frame including at least one movable section, the edge of themovable section being adjacent an edge of another section of the frame,each of said sections having at least two surfaces, the covering on onesurface of said sections extending only to the adjacent edges of thesections, the covering on the other surface of said sections extendingacross said edges to afford a pivot joint means whereby said movablesection may be pivoted with respect to the other sectio-n.

References Cited UNITED STATES PATENTS 2,096,750 10/1937 Lawrence 41-342,560,742 7/1951 Redor 46-'76 2,767,436 10/1956 Noland 46-76 2,802,7648/1957 Slayter et al. 181-33 2,920,682 1/1960 Lindberg 46-76 3,273,2819/1966 Harrison 46-76 OTHER REFERENCES American Modeler, Sketchbook, May1959, vol. 52, p. 37.

American Modeler, Sketchbook, March 1958, p. 10.

ANTON O. OECHSLE, Primary Examiner.

RCHARD C. PINKHAM, F. BARRY SHAY, Examiners. T. ZACK, AssistantExaminer.

